HP-UX 11i v3 LVM Volume Group Migration

Abstract
This white paper describes the data mobility enhancements in LVM. You can now move LVM data
from an existing set of disks or DSFs to a new set of disks or DSFs without any application downtime.
In addition, you can move the data within or across storage frames. This paper is intended for system
administrators or operators who have experience with both HP-UX and LVM.
The HP-UX 11i v3 September 2009 Update provides a new command, vgmove, for volume group
mobility. The vgmove command supports migration of Version 1.0 and 2.x volume groups. This
paper explains how to use the vgmove command to perform the volume group migration.
Overview
The vgmove command enables you to migrate data from an existing set of disks in a volume group to
a new set of disks. You can perform volume group migration online only. The vgmove command is
supported for both Version 1.0 and 2.0 volume groups in standalone and exclusive mode only. For
Version 2.1 and greater volume groups, you can perform vgmove when a volume group is activated
in shared, exclusive, or standalone mode. The volume group migration occurs with the data in place.
Prior to the vgmove command, LVM supported moving of physical volumes within a volume group,
but you needed to perform many configuration steps.
When do you use vgmove?
• To migrate the volume group from one set of disks to another set of disks.
• When the boot disk volume group runs out of disk space for the root volume.
• To migrate data from a smaller storage device to a larger storage device
Prerequisites
Before migrating a volume group, you must meet the following prerequisites:
• The volume group must be activated during migration.
• The volume group must be not be quieseced (both write mode and read-write mode with or without
timeout set). Do not activate the volume group in read-only mode.
• All physical volumes belonging to the volume group must be accessible.
How to use vgmove
1. Take a configuration backup of the volume group using vgcfgbackup -f, as a precautionary
measure. You can use this to recover the initial or original volume group configuration, if ncessary.
Save this configuration backup file in a known location, other than the default location; otherwise,
it might be overwritten by a configuration change done later.
2. Prepare the diskmap file to be used for volume group migration.
The diskmap file specifies the list of source disks from which to move data and the list of
destinations disks to which to move data. You have the option to list only a subset of the existing
physical volumes in the volume group that needs to be migrated to new disks. The format of the
diskmap file is as follows:
source_pv_1 destination_pv_1_1 destination_pv_1_2 ....
source_pv_2 destination_pv_2_1 destination_pv_2_2 ....
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